Disc roll, method for producing the same, and disc member base material

ABSTRACT

A disc roll includes a plurality of annular disc members each defining a hole and having a peripheral surface; and a rotary shaft fitted into the holes of the annular disc members by insertion, whereby the peripheral surfaces of the disc members serve as a conveying surface of the disc roll. The disc members include an inorganic fiber, mica and a clay having a content of particle components that have a particle size of 5 μm or larger of not higher than 30% by weight based on the weight of the clay.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/812,304, filed Mar. 30, 2004, pending, which claims priority ofJapanese Patent Application No. 2003-95983 filed Mar. 31, 2003 andJapanese Patent Application No. 2003-96204 filed Mar. 31, 2003, theentire contents of each of which are hereby incorporated by reference inthis application.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

(NOT APPLICABLE)

FIELD OF THE INVENTION

The present invention relates to a disc roll comprising a plurality ofannular disc members fitted together on a rotary shaft by insertion toform a conveying surface by peripheral surfaces of the above-mentioneddisc members, and particularly to a disc roll suitable for theproduction of high-grade plate glass. Further, the invention alsorelates to a method for producing the above-mentioned disc roll and to adisc member base material for the disc roll.

BACKGROUND OF THE INVENTION

In the production of plate glass, a conveying mechanism for forming theplate glass from a molten state or for slowly cooling the formed glassplate is required. In general, the conveying mechanism is constituted bya conveying roll, and a disc roll has been used as one example of theconveying roll.

FIG. 1 is a schematic view showing one example of a disc roll 10, whichis prepared by stamping out annular discs from a disc member basematerial which is obtained by forming, into a plate form having athickness of several millimeters, an aqueous slurry in which aninorganic fiber, an inorganic filler, a binder, etc. are compounded;fitting these plurality of disc members 12 together on a metal shaft 11acting as a rotary shaft by insertion to form a roll-shaped laminate;and fixing the laminate on the shaft with nuts 15 or the like with theinterposition of flanges 13 arranged at both ends, with some compressionapplied to the disc members 12. The peripheral surfaces of the discmembers 12 function as a conveying surface.

Then, the above-mentioned disc roll 10 is integrated, for example, intoa plate glass production apparatus 100 as shown in FIG. 2, and used formolding and conveyance of plate glass. This plate glass productionapparatus 100 is an apparatus for producing plate glass by continuouslydischarging a glass melt 110 from a linearly opened slit 102 of amelting furnace 101, allowing this discharged strip-shaped glass melt110 to flow downward and to be cooled during the fall to harden it. Thedisc rolls 10 function as a pair of stretching rolls, which hold thestrip-shaped glass melt 110 therebetween to forcibly send it downwards.It is therefore preferred that the disc roll 10 has, as well as heatresistance, some degree of flexibility so as not to damage a glasssurface. A disc roll containing mica particles has been known (seePatent Document 1).

-   Patent Document 1: JP 59-028771 B

As shown in FIG. 2, a pair of the disc rolls 10 hold the strip-shapedglass melt 110 therebetween to forcibly send it downwards. However, thestrip-shaped glass melt 110 is in a semisolid state, so that both endsof a conveying face tend to be conglobated by surface tension.Accordingly, the resulting plate glass is hardened with its centerportion being thin, resulting in deteriorated flatness at both endsthereof. Further, only both ends of the disc roll 10 come into contactwith the plate glass upon conveyance, and the plate glass breaks in somecases by stress concentration to the thick ends thereof.

Further, the disc roll 10 is constantly in contact with thehigh-temperature strip-shaped glass melt 110. By pressing both endsthereof in a high-temperature state for ensuring the surface pressurewith the glass plate, thermal deformation of the shaft 11 occurs. As aresult, the conveying surface also has an uneven surface following theshape of the shaft 11, so that contacts with the strip-shaped glass melt110 take place only locally, thereby causing stress concentration to apart of the plate glass to break the glass plate or to scratch thesurface thereof.

There is a tendency that the area of the plate glass to be produced isbeing increased. With that tendency, the conveying surface of the discroll 10 increases in width, and the shaft increases in length.Accordingly, the influence by surface tension and the degree ofdeformation of the shaft 11 as described above also increase, and it hasincreasingly become difficult to uniformly apply force to the plateglass.

Such problems have not been solved by conventional disc rolls includingthe disc roll described in patent document 1, having flexibilityimparted thereto.

Further, disc rolls become liable to wear out as flexibility is impartedthereto, resulting in a shortened life thereof. Further, in liquidcrystal displays and plasma displays, quality requirements to plateglass are particularly severe, and it becomes a significant problem toprevent contamination of the surface thereof caused by abrasion powder(powder omission) from the disc roll. The disc roll in which importanceis attached to flexibility is liable to wear out, so that the powderomission is liable to occur, which tends to result in a reduced yield.

In order to impart flexibility to the disc roll, it is also possible toreduce the pressure applied at the time when the disc members 12 areloaded on the shaft 11 and compressed from both ends, to thereby lowerthe compressed density. However, such reduced pressure adversely affectsthe durability of the roll, resulting in a shortened roll life.

SUMMARY OF THE INVENTION

The invention has been made in view of the foregoing problems in theconventional techniques.

Accordingly, a first object of the invention is to provide a disc rollwhich can uniformly apply force to plate glass.

A second object thereof is to provide a disc roll excellent in heatresistance and durability, and having moderate flexibility and a longlife, in spite of its low compressed density.

Another object of the present invention is to provide a disc member basematerial for obtaining the above-mentioned disc rolls.

A still other object of the present invention is to provide a method forproducing the disc roll using the above-mentioned disc member basematerial.

Other objects and effects of the invention will become apparent from thefollowing description.

The above-mentioned first objects have been achieved by providing thefollowing disc rolls, methods for producing a disc roll and disc memberbase materials (This aspect of the present invention is hereinafterreferred to as “First Invention”).

(1A) A disc roll comprising:

a plurality of annular disc members each defining a hole and having aperipheral surface; and

a rotary shaft fitted into the holes of said annular disc members byinsertion, whereby the peripheral surfaces of said disc members serve asa conveying surface of the disc roll,

wherein said disc members have a compression deformation rate of 0.05 to0.3 mm under a load of 10 kgf/cm.

(2A) The disc roll according to item (1A) above, wherein said discmembers contain an inorganic fiber in an amount of 20 to 40% by weightbased on the total weight of said disc members and have voids of 30 to70% by volume.

(3A) The disc roll according to item (1A) or (2A) above, wherein saiddisc members contain mica in an amount of 20 to 50% by weight based onthe total weight of said disc members.

(4A) A method for producing a disc roll, comprising the steps of:

forming into a plate form a slurry raw material containing an inorganicfiber in an amount of 20 to 40% by weight to obtain a disc member basematerial;

stamping out a plurality of annular disc members each defining a holeand having a peripheral surface, from said disc member base material;and

fitting said plurality of annular disc members on a rotary shaft byinsertion through the holes and fixing said disc members thereon toobtain a disc roll.

(5A) The method according to item (4A) above, wherein said formation ofthe disc member base material is conducted by a paper-making process.

(6A) The method according to item (4A) or (5A) above, wherein saidslurry raw material contains in an amount of 3 to 15% by weight amaterial which is burnt off by heat applied at the time of burning orupon use.

(7A) A plate-shaped disc member base material, having a compressiondeformation rate of 0.05 to 0.3 mm under a load of 10 kgf/cm.

(8A) The disc member base material according to item (7A) above,containing an inorganic fiber in an amount of 20 to 40% by weight basedon the weight of said disc member base material and have voids of 30 to70% by volume.

(9A) The disc member base material according to item (7A) or (8A) above,containing mica in an amount of 20 to 50% by weight based on the weightof said disc member base material.

In the disc roll of the first invention, the disc member has theabove-mentioned specific compression deformation rate, and thereforedeforms to a moderate degree by contact with glass melt or plate glass,which causes the conveying surface to contact with the glass melt or theplate glass over the whole surface, resulting in the plate glass havingexcellent flatness and no breakage in conveyance.

The above-mentioned second objects have been achieved by providing thefollowing disc rolls, methods for producing a disc roll and disc memberbase materials (This aspect of the present invention is hereinafterreferred to as “Second Invention”).

(1B) A disc roll comprising:

a plurality of annular disc members each defining a hole and having aperipheral surface; and

a rotary shaft fitted into the holes of said annular disc members byinsertion, whereby the peripheral surfaces of said disc members serve asa conveying surface of the disc roll,

wherein said disc members comprise an inorganic fiber, mica and a clayhaving a content of particle components that have a particle size of 5μm or larger of not higher than 30% by weight based on the weight of theclay.

(2B) The disc roll according to item (1B) above, wherein said mica ismuscovite.

(3B) The disc roll according to item (1B) or (2B) above, wherein saidinorganic fiber is present in an amount of 5 to 40% by weight based onthe total weight of said disc members, and said clay is present in anamount of 5 to 55% by weight based on the total weight of said discmembers.

(4B) The disc roll according to any one of items (1B) to (3B) above,wherein said mica is present in an amount of 5 to 60% by weight based onthe total weight of the disc member.

(5B) A method for producing a disc roll, comprising the steps of:

forming into a plate form a slurry raw material to obtain a disc memberbase material, said slurry raw material comprising an inorganic fiber,mica and a clay containing particle components that have a particle sizeof 5 μm or larger in an amount of 30% by weight or less based on theweight of the clay;

stamping out a plurality of annular disc members each defining a holeand having a peripheral surface, from said disc member base material;and

fitting said plurality of annular disc members on a rotary shaft byinsertion through the holes and fixing said disc members thereon toobtain a disc roll.

(6B) The method according to item (5B) above, wherein said formation ofthe disc member base material is conducted by a paper-making process.

(7B) A plate-shaped disc member base material comprising an inorganicfiber, mica and a clay having a content of particle components that havea particle size of 5 μm or larger of not higher than 30% by weight basedon the weight of the clay.

(8B) The disc member base material according to item (7B) above, whereinsaid mica is muscovite.

(9B) The disc member base material according to item (7B) or (8B) above,wherein said inorganic fiber is present in an amount of 5 to 40% byweight based on the weight of said disc member base material, and saidclay is present in an amount of 5 to 55% by weight based on the weightof said disc member base material.

(10B) The disc member base material according to any one of items (7B)to (9B) above, wherein said mica is present in an amount of 5 to 60% byweight based on the weight of the disc member base material.

The disc roll of the second invention is excellent in flexibility andwear resistance, and particularly suitable for the production ofhigh-grade plate glass having a large area, in spite of its lowcompressed density, because fine and uniformly sized clay particlescontained into the disc material exhibits a stronger binding function torestrain other filling materials more firmly in the disc material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing one example of the disc roll of theinvention.

FIG. 2 is a schematic view showing one example of the way of using thedisc roll shown in FIG. 1 (a plate glass production apparatus).

FIG. 3 is a schematic view showing an apparatus used for the measurementof the compression deformation rate in Examples.

The reference numerals used in the drawings represents the followings,respectively.

-   -   10: Disc Roll    -   11: Metal Shaft    -   12: Disc members    -   13: Flanges    -   15: Nuts    -   50: Stand    -   60: Compression Member    -   100: Plate Glass Production Apparatus    -   101: Melting Furnace    -   102: Slit    -   110: Strip-Shaped Glass Melt

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described in detail below.

First Invention

The disc roll of the first invention may have the same structure as thatof a conventional disc roll, and, for example, the disc roll 10 shown inFIG. 1 can be cited. In the first invention, the constituent materialsthereof are adjusted so that the disc member 12 has a compressiondeformation rate of 0.05 to 0.3 mm, preferably 0.08 to 0.2 mm, morepreferably 0.1 to 0.15 mm, under a load of 10 kgf/cm. When thecompression deformation rate is less than 0.05 mm, the disc member 12 istoo hard to cause deformation by contact with the glass melt or theglass plate. On the other hand, when the compression deformation rateexceeds 0.3 mm, the disc member 12 is too soft, resulting in poor wearresistance to bring about so-called powder omission.

The constituent materials of the disc member 12 preferably comprise theinorganic fiber. The inorganic fiber contributes to compressiondeformation of the disc member 12 owing to bending of itself. There isno limitation on the kind of inorganic fiber overwhelmingly excellent inflexibility compared to particle materials, and a variety of inorganicfibers which have hitherto been used for disc rolls can be appropriatelyused. Examples thereof include ceramic fiber, mullite fiber, aluminafiber, silica fiber, silica.alumina fiber, glass fiber and rock woolfiber. The alumina fiber, mullite fiber, silica.alumina fiber and silicafiber are suitable among others because of their excellent heatresistance. It is preferred that these inorganic fibers have an averagefiber diameter of 0.5 to 10 μm, and an average fiber length of 1 mm ormore, from the viewpoint of flexibility. Further, the inorganic fiberscan be used as a combination of two or more thereof as needed.

The content of the inorganic fiber is preferably from 20 to 40% byweight, and particularly preferably from 25 to 35% by weight. When thecontent of the inorganic fiber is less than 20% by weight, the bendingaction of the inorganic fiber itself may become insufficient, resultingin failure to realize the above-mentioned lower limit of the compressiondeformation rate. On the other hand, when the content of the inorganicfiber exceeds 40% by weight, the bending action of the inorganic fiberitself may excessively increase, resulting in the compressiondeformation rate exceeding the above-mentioned upper limit.

Further, in order to bind the inorganic fiber, an inorganic binder ispreferably added. As the inorganic binder, there can be used a clay,glass frit, amorphous cordierite, colloidal silica, alumina sol, sodiumsilicate, titania sol, lithium silicate or liquid glass. Among them, aclay is preferred, because it exerts shape-holding property bycondensation upon drying and because it is sintered by the heat appliedthereto upon use of the disc roll to give a hardening action. Therefore,the balance between the improvement in wear resistance of the discmember 12 and its hardness can be attained. Further, the clay includeskibushi clay, potter's clay and fire clay, and kibushi clay is preferredof these because of its high binder effect and small impurity content.Many of the impurities contained in clay are hard substances, so thatthere is a fear of scratching the plate glass during conveyance.

Further, mica is preferably added. In the disc roll, the shaft 11 onwhich the disc members 12 are fitted together by insertion is made ofmetal as shown in FIG. 1. Accordingly, when the shaft 11 is exposed tohigh temperatures, it thermally expands to elongate along its axialdirection. At this time, the disc members 12 cannot follow theelongation of the shaft 11, because the disc members 12 have a lowercoefficient of thermal expansion as compared to the metal. As a result,the disc members 12 are separated from one another. On the other hand,the mica has an extremely thin layered structure, and releases crystalwater upon heating to cause crystal transformation. In that case, themica tends to expand in its layer direction. This expansion of the micain its layer direction enhances the followabilty of the disc members 12to the thermal expansion of the shaft 11. In order to obtain such aneffect, the mica content is preferably from 20 to 50% by weight, andmore preferably from 25 to 45% by weight, based on the total weight ofthe disc member.

As the mica, there can be used muscovite (K₂Al₄(Si₃Al)₂O₂₀(OH)₄), blackmica, phlogopite (K₂Mg₆(SiAl)₂O₂₀(OH)₄), paragonite, lepidonite orfluorine synthetic mica. With consideration of the above-mentionedfollowability, muscovite is preferred because it releases crystal waterat about 600° C. which is lower than the surface temperature of moltenglass.

The average particle size of the mica is from 5 to 500 μm, preferablyfrom 100 to 300 μm, and more preferably from 200 to 300 μm. When theaverage particle size is within the above-mentioned range, the micaeffectively functions as a plate spring for retaining the stress,applied upon compression loading, between the mica and other constituentmaterials, particularly the inorganic fiber, thereby enabling to furtherenhance the followability to the thermal expansion of the shaft 11 andimproving recovery property after compression deformation.

As described below, the disc member base material is obtained by forminga slurry raw material containing the inorganic fiber etc., and burningit. When a material which is burnt off at the time of burning, such asan organic material which is burnt off at a temperature of 350 to 500°C. or an inorganic material which is burnt off at a temperature of 450to 600° C., is incorporated into the slurry raw material, voids derivedfrom such a material are formed in the disc member 12, which makes itpossible to cause compression deformation more effectively. The organicmaterials which are burnt off at 350 to 500° C. include natural fiberssuch as softwood pulp, organic fibers such as petrochemical syntheticfibers (e.g., a PET fiber and an acrylic fiber), starch, synthetic resinbinders such as NBR emulsion, SBR emulsion, acrylic emulsion and vinylacetate-based emulsion, and organic particles such as polyethylene andpolypropylene. The inorganic materials which are burnt off at 450 to600° C. include crystalline carbon and amorphous carbon, both of whichcan be used in either particle form or fiber form. The percentage ofvoids in the disc member 12 is preferably from 30 to 70% by volume, andmore preferably from 50 to 65% by volume, and the percentage of voidswithin the above-described ranges can be attained by adjusting theamount of the organic fiber, the organic binder or the like contained inthe slurry raw material.

Then, the method for producing the disc roll of the first invention willbe described. The production method is basically conducted in accordancewith a conventional method, and described below with reference to FIG. 1again. First, an aqueous slurry containing the above-mentioned inorganicfiber, the inorganic binder such as the clay, the mica, the organicfiber, the organic binder, etc. is formed into a plate form, and driedand burnt to obtain a disc member base material. At this time, the useof the paper-making process is efficient and preferred. That is, theaqueous slurry is formed into a plate form with a paper-making machine,and dried and burnt. The thickness of the disc member base material canbe appropriately set. The thickness may be similar to that ofconventional one, and is generally from 2 to 10 mm.

Then, annular disc members 12 are stamped out from the disc member basematerial, and these plurality of disc members 12 are fitted together ona rotary shaft 11 made of metal (for example, made of iron) by insertionto form a roll-shaped laminate. Then, they are fixed with nuts 15 or thelike with the interposition of flanges 13 arranged at both ends, withsome compression applied from both ends to the disc members 12. Then,peripheral surfaces of the disc members 12 are ground so as to give apredetermined roll diameter, thereby obtaining a disc roll 10.

Second Invention

The disc roll of the second invention may have the same structure asthat of a conventional disc roll, and, for example, the disc roll 10shown in FIG. 1 can be cited. In the second invention, the disc member12 contains an inorganic fiber, mica and a clay having a content ofparticle components that have a particle size of 5 μm or larger of nothigher than 30% by weight based on the total weight of the clay.

As for the kind of clay, the clays include kibushi clay, potter's clayand fire clay. Among them, kibushi clay is preferred because of its highbinder effect and small impurity content. The clays can be used eitheralone or as a combination of two or more thereof as needed. In thesecond invention, the incorporation of the clay can improve the wearresistance of the disc member 12 owing to the hardening action caused bydrying and heating.

The clay is purified by separation, thereby adjusting the content of theparticle components having a particle size of 5 μm or larger to nothigher than 30% by weight, preferably not higher than 15% by weight andmore preferably not higher than 10% by weight. As for the lower limit,it is most suitable to contain no particle components having a particlesize of 5 μm or larger at all. Such fine and uniformly sized clayparticles exhibit higher binding ability to restrain other constitutingmaterials firmly.

By this separation purification, impurities are also removed at the sametime. In general, the clay which is a natural mineral can be controlledin particle size to some degree by pulverization sizing. However, theclay contains impurities in large amounts, and the impurities containedtherein include, in many cases, those having no sinterability such assilica. In the disc roll 10 upon use, sintering occurs by contact with ahigh-temperature conveying product such as molten glass, therebyallowing hardening to proceed. However, the impurities having nosinterability become a factor of inhibiting the hardening action of thedisc member 12 at this time. Moreover, many of the impurities are hardsubstances, so that there is a fear of scratching the plate glassparticularly during conveyance. The content of impurities is preferablyclose to zero without limit. However, considering the actual situationsof labor, cost, etc., the content of impurities is preferably 10% byweight or less, more preferably 5% by weight or less, and still morepreferably 1% by weight or less based on the weight of the clay.

In order to reduce the content of coarse particles to the specific valueor less as described above, and further to remove the impurities, wetsizing is effective as the separation purification process. Byconducting the wet sizing, impurities different in specific gravity andsize are removed. Furthermore, since the sedimentation velocity variesdepending on particle size, raw clay having a finer particle size and asharper particle size distribution can be generally obtained by the wetsizing than by dry sizing.

As the inorganic fibers, there can be appropriately used a variety ofinorganic fibers which have hitherto been used for disc rolls. Examplesthereof include ceramic fiber, mullite fiber, alumina fiber, silicafiber, silica.alumina fiber, glass fiber and rock wool fiber. Of these,those having excellent heat resistance which include alumina fiber,mullite fiber, silica.alumina fiber and silica fiber are suitable.Further, the inorganic fibers can be used as a combination of two ormore thereof as needed.

Mica is known to be excellent in high elasticity, slidability, wearresistance and heat resistance, and has long been industrially utilizedin various fields. However, in the second invention, mica is added inorder to allow the disc member 12 to follow the thermal expansion of theshaft 11. In the disc roll, the shaft 11 on which the disc members 12are fitted together by insertion is made of metal as shown in FIG. 1.Accordingly, when the shaft 11 is exposed to high temperatures, itthermally expands to elongate along its axial direction. At this time,the disc members 12 cannot follow the elongation of the shaft 11,because the disc members 12 has a lower coefficient of thermal expansionas compared to the metal. As a result, the disc members 12 are separatedfrom one another. On the other hand, mica has an extremely thin layeredstructure, and releases crystal water upon heating to cause crystaltransformation. In that case, mica tends to expand in its layerdirection. This expansion of mica in its layer direction enhances thefollowabilty of the disc members 12 to the thermal expansion of theshaft 11.

As the mica, there can be used muscovite (K₂Al₄(Si₃Al)₂O₂₀(OH)₄), blackmica, phlogopite (K₂Mg₆(SiAl)₂O₂₀(OH)₄), paragonite, lepidonite orfluorine synthetic mica. With consideration of the above-mentionedfollowability, muscovite is preferred because it releases crystal waterat about 600° C. which is lower than the surface temperature of moltenglass.

The average particle size of the mica is from 5 to 500 μm, preferablyfrom 100 to 300 μm, and more preferably from 200 to 300 μm. When theaverage particle size is within the above-mentioned range, the micaeffectively functions as a plate spring for retaining the stress,applied upon compression loading, between the mica and other constituentmaterials, particularly the inorganic fiber, thereby enabling to furtherenhance the followability to the thermal expansion of the shaft 11 andimproving recovery property after compression deformation.

As for the blending of the above-mentioned inorganic fiber, clay andmica, the inorganic fiber is added preferably in an amount of 5 to 40%by weight, more preferably in an amount of 5 to 30% by weight, based onthe total weight of the disc member, the clay is added preferably in anamount of 5 to 55% by weight, more preferably in an amount of 20 to 40%by weight, based on the total weight of the disc member, and the mica isadded preferably in an amount of 5 to 60% by weight, more preferably inan amount of 20 to 55% by weight, based on the total weight of the discmember. The disc roll having a good balance between flexibility and wearresistance can be obtained within these ranges.

Then, the method for producing the disc roll of the second inventionwill be described. The production method is basically conducted inaccordance with a conventional method, and described below withreference to FIG. 1 again. First, an aqueous slurry containing theabove-mentioned inorganic fiber, clay and mica is formed into a plateform, and dried. At this time, the use of the paper-making process isefficient and preferred. That is, the aqueous slurry containing theinorganic fiber, the clay and the mica, and optionally a coagulant aid,an organic fiber, an organic binder, etc. as needed, in predeterminedamounts, and this aqueous slurry is formed into a plate form with apaper-making machine and dried. Thereby, a disc member base material canbe obtained. The thickness of disc member base material can beappropriately set. The thickness may be similar to that of conventionalone and is generally from 2 to 10 mm.

Then, annular disc members 12 are stamped out from the disc member basematerial, and these plurality of disc members 12 are fitted together ona rotary shaft 11 made of metal (for example, made of iron) by insertionto form a roll-shaped laminate. Then, they are fixed with nuts 15 or thelike with the interposition of flanges 13 arranged at both ends, withsome compression applied from both ends to the disc members 12. Then,the peripheral surfaces of the disc members 12 are ground so as to givea predetermined roll diameter, thereby obtaining the disc roll 10.

EXAMPLES

The invention will be further described below with reference to examplesand a comparative example, but the invention should not be construed asbeing limited thereby.

Examples 1A to 9A and Comparative Examples 1A to 2A

An aqueous slurry in which the raw materials shown in Table 1A werecompounded was prepared, and then subjected to a paper-making processusing a cylinder type paper-making machine to obtain a plate-shapedformed product having a size that gives a dimension after drying of 100mm×100 mm×6 mm. The plate-shaped formed product was then dried at atemperature of from 90 to 120° C. for 6 hours to obtain a disc memberbase material. Herein, the raw materials used were specifically as shownbelow.

Aluminosilicate Fiber:

Fineflex bulk fiber manufactured by Nichias Corporation

Muscovite:

Kralite manufactured by Kuraray Co., Ltd.

Kibushi Clay:

Kibushi clay manufactured by Shinmei Industry Co., Ltd.

Organic Fiber (pulp):

Hinton pulp manufactured by Hinton

Organic Binder (starch):

Excell manufactured by Nippon Starch Chemical Co., Ltd.

Organic Particles (polyethylene):

Flo-thene manufactured by Sumitomo Seika Chemicals Co., Ltd.

Carbon Fiber:

Besfight chopped fiber manufactured by Toho Tenax Co., Ltd.

From the disc member base material thus obtained, disc members eachhaving an outer diameter of 80 mm and an internal diameter of 30 mm werestamped out, and fitted together on an iron shaft having a diameter of30 mm and a length of 100 mm by insertion to prepare a column-shapeddisc roll as shown in FIG. 1. Incidentally, the disc members werecompressed from the both ends thereof through flanges 13 so as to give acompressed density of 1.2 g/cm³ and then fixed. The thus obtained discroll was then subjected to the following measurements and evaluations.

Measurement of Percentage of Voids

The percentage of voids was determined from the compressed density ofthe disc roll and the true densities of the raw materials in accordancewith the following equation.

Percentage of voids of roll=1−[(Compressed density of roll)/(Weightedaverage true density of raw materials)]

Measurement of Compression Deformation Rate

The resulting disc roll was supported by a stand 50 at both ends of theshaft 11, and a load of 10 kgf/cm was applied through a compressionmember 60 at a rate of 1 mm/min to a conveying surface constituted bythe disc members 12, as shown in FIG. 3. The compression deformationrate under this state was measured. The results thereof are shown inTable 1A.

Confirmation of Scratches on Glass Surface

Separately, a disc roll of the same type was prepared using each discmember base material, and integrated into a plate glass productionapparatus as shown in FIG. 2 to try to prepare plate glass. Then, thesurface of the resulting plate glass was visually observed to confirmthe presence or absence of scratches. The results thereof are shown inTable 1A.

TABLE 1A Com. Com. Ex. 1A Ex. 2A Ex. 3A Ex. 4A Ex. 5A Ex. 6A Ex. 7A Ex.8A Ex. 9A Ex. 1A Ex. 2A Inorganic Aluminosilicate 20 30 30 30 30 30 3030 40 5 50 Fiber Fiber Mica Muscovite 40 30 30 30 30 30 30 30 20 55 10Filler Kibushi Clay 25 25 25 25 25 25 20 20 25 25 25 Material to OrganicFiber 10 15 15 10 10 10 Be Burnt Off (Pulp) by Burning Organic Binder 55 5 5 5 5 5 5 5 5 (Starch) Organic Particles 10 10 (Polyethylene) CarbonFiber 10 10 Compression (mm) 0.10 0.12 0.14 0.12 0.10 0.13 0.16 0.180.18 0.03 0.35 Deformation Rate Percentage of (% by volume) 60 60 60 5550 60 65 65 60 60 60 Voids Glass Scratch (scratches/m²) 0 0 0 0 0 0 0 00 350 * Note 1) The compounded amounts are shown by “pats by weight”.Note 2) * Unmeasurable because of the development of cracks in glass.

The results shown in Table 1A reveal that the use of the disc rollhaving a compression deformation rate of 0.05 to 0.3 mm according to thefirst invention provides a high-quality plate glass having no scratch onthe surface.

As described above, according to the first invention, there is provideda disc roll excellent in heat resistance and durability, having moderateflexibility and a long life, and particularly suitable for theproduction of the high-grade plate glass having a large area, in spiteof its low compressed density.

Examples 1B to 6B and Comparative Examples 1B to 3B

An aqueous slurry in which the raw materials shown in Table 1B werecompounded was prepared, and then subjected to a paper-making processusing a cylinder type paper-making machine to obtain a plate-shapedformed product having a size that gives a dimension after drying of 100mm×100 mm×6 mm. The plate-shaped formed product was then dried at atemperature of from 90 to 120° C. for 6 hours to obtain a disc memberbase material. Herein, the raw materials used were specifically as shownbelow.

Aluminosilicate Fiber:

Fineflex bulk fiber manufactured by Nichias Corporation

Muscovite:

Kralite manufactured by Kuraray Co., Ltd.

Phlogopite:

Suzolite manufactured by Kuraray Co., Ltd.

Kibushi Clay:

Kibushi clay manufactured by Shinmei Industry Co., Ltd.

Organic Fiber (pulp):

Hinton pulp manufactured by Hinton

Organic Binder (starch):

Excell manufactured by Nippon Starch Chemical Co., Ltd.

From the disc member base material thus obtained, disc members eachhaving an outer diameter of 80 mm and an internal diameter of 30 mm werestamped out, and fitted together on an iron shaft having a diameter of30 mm and a length of 100 mm by insertion to prepare a column-shapeddisc roll as shown in FIG. 1. Incidentally, the disc members werecompressed from the both ends thereof through flanges 13 so as to give acompressed density of 1.2 g/cm³ and then fixed. The thus obtained discroll was then subjected to the following measurements and evaluations.

Measurement of Surface Hardness

The surface hardness (Shore D) of the disc roll was measured inaccordance with ASTM D 2240 using analog hardness testing machineD-model manufactured by High Polymer Chemistry Co., Ltd. The resultsthereof are shown in Table 1B.

Evaluation of Wear Resistance

The disc roll was kept for 180 minutes in a heating furnace maintainedat 900° C., and then allowed to cool to room temperature, followed byrubbing with hand. The wear resistance was evaluated by touch at thattime. The evaluation criteria are as follows:

Good: A powder is transferred to hand by rubbing.

Excellent: Neither transfer nor powder omission is observed.

The results thereof are shown in Table 1B.

Evaluation of Followability to Shaft

Further, on a roll surface after the above-mentioned evaluation of wearresistance, the total width of clearances between disc members wasmeasured to evaluate followability. The evaluation criteria are asfollows:

Excellent: The total width is 0 mm.

Good: The total width is not larger than 1 mm.

Fair: The total width exceeds 1 mm but is not larger than 2 mm.

Poor: The total width exceeds 2 mm.

The results thereof are shown in Table 1B.

Confirmation of Scratches on Glass Surface

Separately, a disc roll of the same type was prepared using each discmember base material, and integrated into a plate glass productionapparatus as shown in FIG. 2 to try to prepare plate glass. Then, thesurface of the resulting plate glass was visually observed to confirmthe presence or absence of scratches. The results thereof are shown inTable 1B.

TABLE 1B Com. Com. Com. Ex. 1B Ex. 2B Ex. 3B Ex. 4B Ex. 5B Ex. 6B Ex. 1BEx. 2B Ex. 3B Inorganic Aluminosilicate 20 30 30 30 20 10 30 30 20 FiberMica Muscovite 45 35 25 25 25 25 25 Phlogopite 55 25 Clay KibushiElutriated (Note 2) 20 30 40 50 Clay Elutriated (Note 3) 10 10 NotTreated 30 30 40 Organic Fiber 10 10 10 10 10 10 10 10 10 Organic Binder5 5 5 5 5 5 5 5 5 Surface Hardness (Shore D) 40 40 45 50 55 60 50 50 55Glass Scratch (scratches/m²) 0 0 0 0 0 2 120 105 350 Wear ResistanceGood Good Good Excellent Excellent Excellent Excellent ExcellentExcellent Followability to Shaft Good Excellent Excellent ExcellentExcellent Excellent Fair Excellent Excellent Overall Evaluation GoodGood Good Excellent Excellent Good Poor Poor Poor Note 1) The compoundedamounts are shown by “pats by weight”. (Note 2) The content of particlesof 5 μm or larger in size is 30% by weight or less. (Note 3) The contentof particles of 5 μm or larger in size is 15% by weight or less.

The results shown in Table 1B reveals that the disc roll of each Examplecontaining the mica and the clay having a content of particle componentsof 5 μM or larger of not higher than 30% by weight has practicallyproblem-free heat resistance and wear resistance, does not scratch theglass surface, and has moderate flexibility.

As described above, according to the second invention, there is providedthe disc roll excellent in heat resistance and durability, havingmoderate flexibility and a long life, and particularly suitable for theproduction of the high-grade plate glass having a large area, in spiteof its low compressed density.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

1. A method for producing a disc roll, comprising the steps of: forming into a plate form a slurry raw material to obtain a disc member base material, said slurry raw material comprising an inorganic fiber, mica and a kibushi clay containing particle components that have a particle size of 5 μm or larger in an amount of 30% by weight or less based on the weight of the kibushi clay; stamping out a plurality of annular disc members each defining a hole and having a peripheral surface, from said disc member base material; and fitting said plurality of annular disc members on a rotary shaft by insertion through the holes and fixing said disc members thereon to obtain a disc roll, whereby the peripheral surface of said disc members serves as a conveying surface of the disc roll, wherein the kibushi clay is either elutriated or subjected to a wet sizing separation purification process, and the kibushi clay is configured to be sintered by heat applied thereto upon use of the disc roll to give a hardening action, wherein said kibushi clay has a content of impurities of 10% by weight or less based on the weight of the clay, wherein said inorganic fiber is present in an amount of 20 to 40% by weight based on the total weight of said disc members, and said kibushi clay is present in an amount of 20 to 40% by weight based on the total weight of said disc members, and wherein said mica is present in an amount of 20 to 35% by weight based on the total weight of the disc member.
 2. The method according to claim 1, wherein said formation of the disc member base material is conducted by a paper-making process.
 3. The method for producing a disc roll according to claim 1, wherein said mica is muscovite.
 4. The method for producing a disc roll according to claim 1, wherein the amount of said kibushi clay is 30 to 40% by weight based on the total weight of said disc members.
 5. The method for producing a disc roll according to claim 1, wherein said kibushi clay has a content of particles with a particle size of 5 μm or larger of not higher than 15% by weight based on the weight of the kibushi clay.
 6. The method for producing a disc roll according to claim 1, wherein said mica has an average particle size of 5 to 500 μm.
 7. A plate-shaped disc member base material comprising an inorganic fiber, mica and a kibushi clay having a content of particle components that have a particle size of 5 μm or larger of not higher than 30% by weight based on the weight of the kibushi clay, the kibushi clay being either elutriated or subjected to a wet sizing separation purification process, and the kibushi clay being configured to be sintered by heat applied thereto upon use of a disc roll formed therefrom to give a hardening action, wherein said kibushi clay has a content of impurities of 10% by weight or less based on the weight of the clay, wherein said inorganic fiber is present in an amount of 20 to 40% by weight based on the total weight of said disc member base material, and said kibushi clay is present in an amount of 20 to 40% by weight based on the total weight of said disc member base material, and wherein said mica is present in an amount of 20 to 35% by weight based on the total weight of the disc member base material.
 8. The disc member base material according to claim 7, wherein said mica is muscovite.
 9. The plate-shaped disc member base material according to claim 7, wherein the amount of said kibushi clay is 30 to 40% by weight based on the total weight of said disc member base material.
 10. The plate-shaped disc member base material according to claim 7, wherein said kibushi clay has a content of particles with a particle size of 5 μm or larger of not higher than 15% by weight based on the weight of the kibushi clay.
 11. The plate-shaped disc member base material according to claim 7, wherein said mica has an average particle size of 5 to 500 μm.
 12. A method for producing a glass using a disc roll as a conveying roll, wherein the disc roll comprises a plurality of annular disc members each defining a hole and having a peripheral surface and a rotary shaft fitted into the holes of said annular disc members by insertion, whereby the peripheral surface of said disc members serves as a conveying surface of the disc roll, wherein said disc members comprises an inorganic fiber, mica and a kibushi clay containing particle components that have a particle size of 5 μm or larger in an amount of 30% by weight or less based on the weight of the kibushi clay, wherein the kibushi clay being either elutriated or subjected to a wet sizing separation purification process, and the kibushi clay being configured to be sintered by heat applied thereto upon use of the disc roll to give a hardening action, wherein said kibushi clay has a content of impurities of 10% by weight or less based on the weight of the clay, wherein said inorganic fiber is present in an amount of 20 to 40% by weight based on the total weight of said disc members, and said kibushi clay is present in an amount of 20 to 40% by weight based on the total weight of said disc members, and wherein said mica is present in an amount of 20 to 35% by weight based on the total weight of the disc members. 